The present invention relates generally to electromagnetic actuators, and more particularly, to a rotary actuator having a flux path formed in part by a plurality of stamped laminations.
The desirability of and need for a rotary electromagnetic actuators has been recognized for years. A factor in the effectiveness of rotary electromagnetic actuators is the ability of the actuator to convert electromagnetic forces into useful output torque. That is, the efficiency of the actuator in converting electromagnetic forces into useful output torque is of primary importance. One primary factor in converting electromagnetic forces into useful output torque is the creation of an efficient flux path that allows magnetic flux to easily flow between components of the actuator with minimal reluctance.
Typically, rotary actuators include a stator machined from steel with magnetic properties that allows flux to move in any direction through the steel. Such a one-piece construction of the stator results in an efficient motor design. As shown in FIG. 1, a prior art rotary actuator 100 includes a solid, machined stator 102 that is positioned adjacent to a rotor 104 such that magnetic flux moves through three sides of the solid stator 102 and through the rotor 104, as is shown by magnetic flux path 106. That is, the magnetic flux travels through a stator outer post 108, across rotor 104, down a stator center post 110, across a lower lateral section of stator 102, and back to stator outer post 108 via a connecting portion 112. While such a construction does provide a relatively efficient flux path, it requires that stator 102 be formed as a complex part. Such complex stator designs that are machined from steel are time consuming to produce and result in an increased part cost. That is, with this type of construction, the stator is machined from a single piece of bar stock. Not only is it time consuming to machine such a piece, the initial material costs are relatively high. With increasing labor and material costs, this construction can become prohibitively expensive.
Therefore, a need exists for a stator design that is efficiently constructed and cost effective, while providing a magnetic flux path having low reluctance so as to maximize the ability of the actuator to convert electromagnetic forces into useful output torque.